The 128 orchids illustrated in this work were collected from the wild in many localities by the late John S. Ball, mainly during the early 1950s when he worked as a forester in the Melsetter area close to the Chimanimani Mountains in Zimbabwe. Many of the species from this area are recorded to the North in the Flora of Tropical East Africa floristic region and to the South in the Republic of South Africa, particularly in KwaZulu-Natal. In 1978 John Ball's work on epiphytic orchids from this region was published in the book Southern African Epiphytic Orchids. The present work is edited by Jane Browning (John Ball's sister) assisted by Esmé Hennessy.